BTW I regret that only recently I found this
software, suggested by
Raymond. It opens up a plethora of possibilities through mouse gestures.
For example, now when I double-click a book in Calibre it will open instantly with Sumatra or Xchange Editor - my system default viewers for the main formats. And if I want to read, highlight etc., I do an 'up' mouse gesture over the book in cover grid, which will open the internal ebook viewer. For metadata download, I have a 'down' gesture, and so on. Edit Metadata is 'up to the left', as shown below:
